GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2008 🢒 Silverado - 2WD 🢒 Roof 🢒 Sunroof 🢒 Power Sunroof Inoperative

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

B+

1

1

--

--

Ignition

1

1

3

--

Close Switch Signal

1

1

1

--

Express Switch Signal

2

2

2

--

Open Switch Signal

1

1

1

--

Vent Close Switch Signal

1

1

1

--

Vent Open Switch Signal

1

1

1

--

Sunroof Switch Ground

--

1

--

--

Sunroof Motor Ground

--

1

--

--

1. Power sunroof malfunction

2. Express open and close inoperative

3. Power sunroof operates with ignition off

Circuit/System Description

The sunroof module supplies each of the sunroof switch signal circuits with a 12-volt reference. When a switch is pressed the signal circuit is pulled low signaling the sunroof open or close request. The module determines the motor direction based on inputs received from the sunroof switch. When the modules reverse the polarity of the applied voltage, the motor reverses direction.

Diagnostic Aids

Prior to performing sunroof system circuit diagnosis, perform the Sunroof Motor/Actuator Initialization/Teach Process .

Reference Information

Schematic Reference

Sunroof Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Sunroof Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification
  1. With the sunroof in the closed position, press the sunroof open switch. The sunroof should open.
    2. ⇒If the sunroof does not open, refer to Power Sunroof Malfunction.
  2. With the sunroof in the open position, press the sunroof close switch. The sunroof should close.
    3. ⇒If the sunroof does not close, refer to Power Sunroof Malfunction.
  3. With the sunroof in the closed position, operate the sunroof express open feature. The sunroof should fully open.
    4. ⇒If the express open feature does not function, refer to Power Sunroof Express Feature Malfunction.
  4. With the sunroof in the open position, operate the sunroof express close feature. The sunroof should fully close.
    5. ⇒If the express close feature does not function, refer to Power Sunroof Express Feature Malfunction.
  5. Crew cab only - with the sunroof in the closed position, press the sunroof vent open switch. The sunroof should open to the vent position.
    6. ⇒If the sunroof does not open, refer to Power Sunroof Malfunction.
  6. Crew cab only - with the sunroof in the vent open position, press the sunroof vent close switch. The sunroof should close.
    7. ⇒If the sunroof does not close, refer to Power Sunroof Malfunction.

Circuit/System Testing

Important: Because of the accessibility of the sunroof switch, perform the sunroof switch component test before beginning the Circuit/System Testing.

Power Sunroof Malfunction

  1. Ignition OFF, disconnect the harness connector at the sunroof module .
  2. Test for less than 5.0 ohm between the ground circuit terminal 1 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Verify that a test lamp illuminates between the B+ circuit terminal 6 and ground.
    4. ⇒If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, replace the fuse and replace the sunroof module.
  4. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 3 and ground.
    5. ⇒If the test lamp does not illuminate, test the ignition circuit for an open/high resistance. If the circuit tests normal, refer to Retained Accessory Power (RAP) Malfunction .
  5. Ignition OFF, connect the harness connector at the sunroof module.
  6. Disconnect the harness connector at the sunroof switch.
  7. Test for less than 5.0 ohm between the ground circuit terminal 5 and ground.
    8. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.

    Important: Apply ground to the module for no longer than 2 seconds at a time or the module could be damaged.

    When performing the following tests, make sure that the sunroof or sunshade is not at its end of travel position by switching the grounded jumper to the other signal circuit if the sunroof or sunshade does not move in one direction.

  8. Ignition ON, momentarily install a 10-amp fused jumper wire between the signal circuit terminal 6 and ground. The sunroof should move.
    9. ⇒If the sunroof does not move, test the signal circuit for a short to ground, short to voltage or an open/high resistance. If the circuit test is normal, replace the sunroof module.
  9. Momentarily install a 10-amp fused jumper wire between the signal circuit terminal 4 and ground. The sunroof should move.
    10. ⇒If the sunroof does not move, test the signal circuit for a short to ground, short to voltage or an open/high resistance. If the circuit test is normal, replace the sunroof module.
  10. Crew cab only - with the sunroof in the fully closed position, momentarily install a 10-amp fused jumper wire between the signal circuit terminal 2 and ground. The sunroof should vent open.
    11. ⇒If the sunroof does not move, test the signal circuit for a short to ground, short to voltage or an open/high resistance. If the circuit test is normal, replace the sunroof control module.
  11. Crew cab only - momentarily install a 10-amp fused jumper wire between the signal circuit terminal 8 and ground. The sunroof should close.
    12. ⇒If the sunroof does not close, test the signal circuit for a short to ground, short to voltage or an open/high resistance. If the circuit test is normal, replace the sunroof control module.
  12. If all circuits test normal, test or replace the sunroof switch.

Power Sunroof Express Feature Malfunction

  1. Ignition OFF, disconnect the harness connector at the sunroof switch.
  2. Ignition ON, with the sunroof in the closed position, connect a 3A fused jumper wires between both signal circuits listed below and ground for less than 1 second. The sunroof should express open.
    3. • Terminal 1
    • Terminal 6
    ⇒If the sunroof does not express open, test the signal circuit terminal 1 for a short to voltage or an open high resistance. If the circuit tests normal, replace the sunroof module.
  3. Ignition ON, with the sunroof in the closed position, connect a 3A fused jumper wire between both signal circuits listed below and ground for less than 1 second. The roof should express open to the vent position.
    4. • Terminal 1
    • Terminal 4
    ⇒If the roof does not express open to the vent position, test the signal circuit terminal 1 for a short to voltage or an open high resistance. If the circuit tests normal, replace the sunroof module.
  4. If all circuits test normal, test or replace the sunroof switch.

Component Testing

Sunroof Switch

  1. Ignition OFF, disconnect the harness connector at the sunroof switch.
  2. Test for infinite resistance between the switch terminals listed below and the ground circuit terminal 5 with the switch in the neutral position.
    3. • Express open/close terminal 1
    • Sunroof close terminal 4
    • Sunroof open terminal 6
    • Crew cab only - vent close terminal 8
    • Crew cab only - vent open terminal 2
    ⇒If not the specified value, replace the sunroof switch.
  3. Test for less than 5 ohms between the switch terminals listed below and the ground circuit terminal 5 with the switch in the appropriate position.
    4. • Express open/close terminal 1
    • Sunroof close terminal 4
    • Sunroof open terminal 6
    • Crew cab only - vent close terminal 8
    • Crew cab only - vent open terminal 2
    ⇒If greater than the specified value, replace the sunroof switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Sunroof Motor/Actuator Replacement
    •  Sunroof Switch Replacement
    •  Control Module References for sunroof module replacement, setup, and programming